Mettaton's Check-Up (smut)
by TheKarin
Summary: Just a smutty one-shot of Alphys and Mettaton(EX) that I felt like doing. Contains dual-penis, don't read if that kind of thing weirds you out. Also my headcanon is Alphys is bisexual, so if that bothers you go away lol.


Alphys' fingers were a blur across her keyboard, the rapid tip-tapping filling up the silence of her mostly empty laboratory. Her enthusiasm was on overdrive, evident by the light sheen of sweat across her brow as words poured down the word document she was currently using. Page after page had been filled with text, but it wasn't science she was working on. No inventions or notes for future experiments. From top to bottom the document had been filled with her most important pastime after anime.

 _–her tongue ran across hard, muscled flesh, drenched with sweat. She could taste it, and the flavour sent shivers down her spine. The noise of pleasure spurred her into giving another lick, this time dropping lower until–_

"Alphys!"

"Huh?! Wh-What?!" Jumping back away from her computer screen, the scientist sat up straighter and peered over her shoulder. Leaning against the railing of the slowly chugging escalator was Mettaton EX, his arms crossed against his chest and a slight frown on his face. When the escalator reached the landing he stepped off it smoothly, reaching up to flick a few fingers through his glossy hair as he made his way to Alphys' desk, who at the time was trying to hide the open documents of her most recent fanfiction to the bottom of her screen. "Oh… It's just you, Mettaton."

" _Just me_?" A slim, sculpted brow quirked slowly as he came to a stop at the corner of her desk, resisting the urge to smirk at the way the yellow monster began to sputter and tug at the sleeves of her labcoat.

"I-I didn't mean that in a bad way, of course. I w-was just…not expecting you, is all." She coughed and quickly adjusted her glasses, another nervous habit. The woman was full of them, each one more easily readable than the last.

"Not expecting me? My daily tune-up is scheduled for today. Ten minutes ago, in fact. I was waiting downstairs for you, sweetheart.~" Mettaton tried his best to sound as put off as possible, the lights on his chest beeping a sad, blue tint while he pouted to the scientist. The corners of his mouth lifted slowly when Alphys shook her head in disbelief, checking and double-checking the current time from her computer.

"O-Oh! I-I'm so sorry, Mettaton. I completely forgot! I had been..a-ah..so busy with my work. Y-You know how it goes, heh…" She fidgeted, turning her computer chair to face him again. She tried not to move when Mettaton shifted his eyes towards her screen for a moment and stared for a long time, still looking rather amused.

"Riiight. So busy writing more _smutty fanfiction_ for your blog, right?" He asked casually. Alphys' cheeks flushed a dark red, her flustered rambling returning with a vengeance.

"O-Of course not! Aheh…d-don't joke about stuff like that, Met." She slapped a claw against her monitor to hit the power button, just incase he decided to check for himself. Try as she like to hide it, there was no mistaking that glint in his eye. He knew all about her habits after all. It was a wonder she tried so hard to hide herself from him. Him, of all people. "W-We can still do the check-up. Come on, my things are downstairs." She started to rise, stopping when Mettaton lifted a hand. She narrowed her eyes nervously, but her brows quickly shot up when the bot pulled his freehand out from behind himself and offered her a small case of tools.

"There's no need, Alphy. I brought your tools right here. I figured you might be…busy, afterall." He grinned slowly, generating a fresh new blush across the female's cheeks. As he used the toolcase to shove aside Alphys' keyboard, she was left staring up at him in wonder as he lowered himself onto her desk beside it. Kicking one leg up to fold across the other. "You're welcome.~" He purred, when she remained silent.

She'd gone completely quiet, staring up at Mettaton as he leaned back on his hands atop her desk as if he was posing for a photoshoot. Looking so glamorous and beautiful that it was almost painful to keep staring, like gazing directly into the sun. With little to no effort he commanded attention, able to make even the harshest monster root for him with that smirk alone. She admired him so much for that. And yet she was technically his creator, in a way. Would she be able to take some of the credit for his greatness? Or had it simply been inside him all along? When she realized he was still grinning down at her with a tilt of his head, she snapped her jaw shut and sat up straight again, sweat at her temples.

"O-Oh. Right. Sure, I can do it here I guess. If you're in a hurry." She fished out a few tools from her case and scooted her chair closer to him, trying her best not to brush her arm against his thigh as she reached towards his soulbox. Even with her chair lifted it was rather difficult to reach his abdomen like this, having been used to him laying down on the examination table instead of sitting upright like he was. Mettaton must have noticed how she was struggling to make use of those short arms in this position, he chuckled. A noise that startled her into looking up at him, glasses sliding down her nose.

"Here, do it like this, darling.~" The robot spoke in a low tone as one long leg lifted high up in the air. Alphys jumped, flush covering her cheeks as Mettaton's spiked boot landed on the other side of her, pushing her computer chair until she was trapped between his legs, giving her ample room to reach his soul. "Much closer, right?" He chuckled as Alphys stammered and shifted in her chair, trying and failing to appear calm about this situation.

She could feel sweat running down her spine, unable to stop the trembling in her fingertips. It was closer, true. But more than being able to reach his soulbox in his position, she was also embarrassingly close to his crotch. And despite being made of various types of metal, there was a telltale warmth to the legs resting on either side of her. But she couldn't tell him that. Couldn't say a damn word of it, knowing just how much MTT loved to tease her about her shyness. So instead she swallowed, audibly, and leaned back to him. Hesitating when the robot seated before her spread his legs a little further apart.

Jaw tight and aching, Alphys flexed her fingers a little before gently opening up the latch to Mettaton's soulbox, the brightly glowing heart pulsating inside. Distracted by the pretty purple hue, she relaxed and smiled, reaching in with her tools to gently secure any loose wires and clearing out dust and debris. Spaz or not, she prided herself on her work. It steadied her hands, her heart, her mind. She felt at ease when she was working. And damn her if a job well done didn't leave her feeling…useful. She hadn't even flinched when Mettaton rested his hand on her hair, gently petting her head while she worked. He was the touchy-feely type and though it often made her feel nervous, she was mostly used to it by now. He must have been happy to see the scientist smile like she was, knowing just how hard it was for Alphys to find something to feel proud of these days.

But the peacefulness of the scene was quickly shattered when Alphys accidentally touched her tiny screwdriver to a sensitive wire, a light spark emitting within the soulbox.

Immediately, Mettaton's body shuddered and he dug his fingers into Alphys' hair, groaning deep in his throat. The sound of it, surprise layered heavily with pleasure, caused the spastic scientist to nearly drop her tools, a dizzying wave clouding through her brain. Her muscles tensed for a second or two, but she quickly pulled her hands away and looked up at him, face hot and sweaty with embarrassment.

"Oh god, I-I'm sorry Mettaton! I d-didn't mean to!" She stammered, heart skipping a beat at the look on Mettaton's face, smirking down at her between his thighs.

"Don't worry about it, love. _It's fine when you do it.~_ " He hummed to her, making her even more breathless by the way pleasure was weaving through his words. Like someone who had just come out of a really, really good massage. Her fingers twitched nervously. Was he just teasing her again? Or had that little zap really felt good? It was difficult to tell how much he could feel in his current state, if robots experienced pleasure and pain like humans and monsters did. But according to him, he did. And often.

"W-Well I'm still sorry. Y-You can go now, you're all g-good." She swallowed again, wondering idly to herself why her mouth was full of so much saliva today. When she realized Mettaton wasn't getting up, wasn't pulling his hand away from her hair, she started to scoot her computer chair backwards. Gasping softly as Mettaton's legs stopped her, reeling her back in slowly. As she twitched her gaze up to his face again, her eyes widened, breath leaving her in a rush. The glamorous robot was still smirking down at her, but the expression had changed somewhat; his vibrant eyes practically glowing, lightly fanged teeth exposed with his widening smile. Helpless and awestruck, Alphys could do nothing except watch as he reached up with one hand and brought a fingertip to his chest, circling a particular button that caused her whole body to twitch in reaction. The button was the same white color as the others, but only Alphys and Mettaton knew what it did. _What was he…doing?_

"It's been a long time, Alphy. When are we gonna do _that_ again?" Mettaton purred. He didn't press his finger into the button, just toyed with the possibility. Alphys couldn't look away from the sinful glide of his fingertip.

"Th-That? W-We…W-Well a-ah…" She was stammering so much she needed to take a break to swallow, her shallow breaths making it difficult to bring in enough air to her lungs. When Mettaton suddenly pushed in the button and and array of lights flickered on his chest, Alphys squeaked and jerked back in her chair, no place to run.

"Come on.~ Aren't you the one who said it's good for my…circuits~?" He teased, running his fingers down his chest while a soft mechanical whirr was heard within his crotch. They both glanced down to watch as a compartment opened up on his crotchplate, just in time for Mettaton's hand to reach and wrap his fingers around the long metal cock that began erecting from it. He helped ease it free with gentle pumps of his fist, tugging on the metal shaft while he watched Alphys stare in a stunned silence. A playful chuckle low in his throat. Although easing it right into the scientist's mouth like this would be easy as pie, the way her thighs seemed to be trembling so fiercely distracted him even more. "There's no need to hold back. Come here, daring."

Alphys squealed in surprise when Mettaton scooped her up from her computer chair, carrying her with ease towards the square at the other end of the room. Hitting a button with his hip before he neared, the box shuddered and unfolded from it's previous shape in order to return to it's original state as a bed, clean and tidy. As Alphys was lowered onto it she was still unable to look away from Mettaton's newly exposed cock. Embarrassment fluttering around with eagerness in her belly. Sure it had been her creation, but the original idea had been Mettaton's! At least, she thinks. It was difficult to remember when and where this add-on had been implemented, but ever since then the flamboyant cyborg had insisted on 'testing it out' with Alphys. To ensure it was still working, or so he claimed.

Still in a stunned silence she could do nothing but lie there as he grabbed the bottom of her sweatpants and yanked them off, tossing the over his shoulder and running a hand through his hair. Fluster burned at her cheeks as he left her like that, making her remember a time when he said he preferred that she keep the labcoat on while they did this. Perhaps he enjoyed making her keep it on because he figured she would always think about what they did while she wore it. Which was…somewhat true, try as she like to ignore it.

"See now, isn't that better, dear Alphy?" Mettaton's voice shocked her out of her thoughts, the deep rumble of it running down her spine as he leaned down to her, easing her legs apart. While his surprisingly warm lips traveled over her cheek, Alphys shuddered and gasped, tilting her head to the side. Seeing that as an invitation, he casually brushed kisses down her jaw and to her neck, relishing the way every touch seemed to effect her more strongly than the last. She really was quite the sensitive creature. Even the light touch of his bulbous cockhead brushing against the crotch of her panties seemed to cause her to jolt in response. The thin, painfully plain white cloth already damp with need. Stutter and push all she like, she was quite the lusty woman. And that shy, twitching female was in the hands of a master.

Letting him take her for a ride, Alphys whimpered softly and relaxed against the bed. Letting Mettaton gently unbutton her labcoat just so that his nibbling smooches could travel beneath her t-shirt and he could sink his fangs against her warm shoulder. The yip of pleasure that escaped her caused him to growl with delight, wanting to tear moan after moan from her throat until she was hoarse. His own need burning within him, clever fingertips reached between their bodies to peel Alphys' panties aside, hissing in pleasure as the tip of his metal cock came into contact with the unbearable heat of the scientists drooling slit. He teased them both like this for a second or two, sliding the tip up and down across her wet flesh and letting it flick against the tiny nub of her clit until she was bucking beneath him. Though he'd love to continue nipping and nibbling against her sensitive flesh, he straightened his back in order to peer down at her. Finding her expression during their 'tests' to be the most delicious thing of all.

Tortuously slow, Mettaton began to ease the tip of his metal cock inside of Alphys, watching her twitching body arch and shudder beneath him as she bit at her bottom lip in efforts to keep her noises silent. He tutted softly, ensuring that by the time he was finished, she would be wailing loud enough that Asgore himself could hear it. As the thick metal shaft split her drenched folds and slipped in deeper, he rested a hand against her hip to steady her body for his penetration. But it was difficult. She squirmed so much, quick little gasps on her tongue and mindless babbling sprinkled in here and there. He loved watching her fly apart so easily. Craved seeing her lose it more than he craved the spotlight. Oh, what a beauty it would be if he could have the fame and fucking both in one. Ravaging Alphys' painfully tight little entrances to an audience of hundreds, thousands, all cheering for him to make her scream. The mere thought of it caused Mettaton to briefly lose himself, thrusting his hips against her until his crotch was flat against hers, cock buried to the hilt.

"A-Ahh! M-Mettaton!" Alphys cried, startled by the sudden fullness of him claiming her body. He could feel her inner twitches all along his shaft, her tight walls trying desperately to relax around the thick intruder stretching her apart.

"S-Sorry, love.." he growled softly, biting at his bottom lip as he pulled his hips back slowly, watching as Alphys writhed in agony towards the loss of it. "It just _feels so._.." Grunting, he thrust back into her, sparks of energy zinging up his spine from the way she squealed in pleasure. Both hands reaching down to hold onto her hips, Mettaton began grinding his hips steadily, thrusting in and out of Alphys at an even pace. Watching the contact of pink flesh and silver metal, sliding wetly from between her twitching folds. He wasted no time in increasing that pace, his hips working like a machine to drill himself into his scientist until her trembling hands reached down to grip his wrists, holding on.

He couldn't stop himself, wanting more and more. Soon he was all out slamming himself inside of Alphys, the pat of metal slapping rhythmically against flesh filling the room. Occasionally he changed the angle of his thrusts, dipping low and jackhammering forward a few dozen times while assaulting that spot inside of Alphys that had her screaming before she could slap a hand over her mouth. Mettaton's mind was on fire with satisfaction, wanting her mindless with pleasure.

"Alphy…" He groaned softly, his thrusting hips slowing. When each thrust was once again a steady grind, he bucked his hips forward once, hard, in order to catch her attention.

"Ahh! Wh-What?" She panted, lifting her head up from the bed. She was already a drooling mess, eyes dazed and confused. But still he wanted more. Reaching between them, he made sure she was watching as he pressed another button, relishing the way her unfocused eyes suddenly cleared and widened in surprise. While still inside of her, Mettaton's cock shifted downward an inch or two, making room for a new addition to this lewd little party. A second shaft, the exact same thickness and length as the one beneath it, began to thrust outward from his body to join the first. A clear liquid was already dripping from the tip and creating a glossy sheen down the length of it, twitching in anticipation to join the fun. Slowly, he pulled his hips back. Groaning low in his chest until his first cock popped free from Alphys' body and sprang upward, dripping with their combined juices and looking ready for more.

He watched Alphys as she stared at the dual cocks for a moment, then glanced up at his face. When the sensual robot waggled his brows at her teasingly, she rewarded him with a heavy blush and nodded, knowing exactly what he wanted. He continued to stare as the scientist began to shift and roll over onto her knees before him, satisfaction a hungry fire in his chest. He helped get her into place, watching her body tremble to give away her anticipation toward what was to come.

"D-Don't forget t-t-to…"

"Ssshh. I know.~" He hushed her softly, and the woman lowered her head towards the bed, her wide hips safely in his clutches. He ran his palms over the thickness of her behind for a moment and made sure to shift her tail to the side so he could see better. Pushing the cheeks together before spreading them apart, he let the lower cock, still covered in her juices, slide between her plump asscheeks. He thrust a few times to make sure the fluids mixed and spread along her holes before reaching down to ease that length right back into her pussy. Aphys shuddered in response, but she was being a lot more hesitant than before. Dual cocks was still rather new for them both. But Mettaton always made sure to prepare her before entering with the second. So for a while he simply pumped inside of her with one of his metal cock, letting the second one hotdog between those cheeks, watching the shiny silver shaft slide back and forth and occasionally lifting it up to slap back down against the meaty flesh once or twice.

Continuing to rock his hips into her rhythmically, he let her return to that state of mindless pleasure with each sinfully fluid glide of his hips, rolling against her and rocking her against the bed. Once he was satisfied with the panting moans and the way her claws were digging into her rumpled sheets, he slowed his thrust down again. Using a thumb to push down his upper cock until the tip could prob the tight pucker of her asshole. Thanks to the shaft's eager leaking, he could smear the slippery liquid against her second entrance and continue toying with it, experimenting with prodding a little harder each time. He could feel Alphys begin to tighten up, but he didn't stop. Wedging that thick, pink cockhead into the tight ring of her sphincter and thrusting gently. Pushing back and forth in short bucks so that he could ease her into being stretched. It wouldn't take much, but he kept at it diligently. Rocking slowly, gently. Occasionally testing her by shoving in more. And savouring her surprised squeak in response.

Finally he felt himself reach the hilt, stilling as both of his cocks were firmly implanted inside her body. Alphys was panting, holding onto the bed so tightly her arms were shaking. Mettaton smirked, stroking a hand over her plump ass to ease her nervousness.

" _Good girl_." he praised her. "You took it all so easily. Can you _feel_ it?" Unable to help teasing her, the whimper she responded with caused his circuits to hum with pleasure. "I'm going to start moving now. Ready?" He whispered affectionately, not waiting for a reply as his hips pulled back slowly. Lips parted on a gasp, bliss registered in his robot body like a wave from head to toe. He pulled back until just those twin cockheads remained inside. Committing that sight to memory just before he thrust back in. Bottoming out within her in one quick pump. She squealed, he groaned. And like that he fell back into that mindless need for higher reaches of pleasure. Lost.

Tucking his head down, Mettaton rammed into Alphys. Each rhythmic pump designed to make her scream. His cocks knew instinctively where her most sensitive spot were, and they assaulted them on each thrust inward. Even as she tightened up around him, he couldn't stop himself. Bucking his hips against her ass and drilling her downward into the bed until his hands had to reach down in order to yank her hips up and against him so he could continue to pump at the perfect angle. His hair was a mess from all the movement, but he couldn't reach up to fix it, forced to stare through the dark locks at the bouncing ass in his lap as he ravaged his poor little scientist. Storing each and every moan and squeal into his memorybanks. When he realized that she would respond to each one of his hungry growls with a sudden clench of her muscles around his cocks, he grinned slowly. Tossing his head back and groaning to the ceiling loud enough that Alphys seemed to lose herself. What a little pervert, so delighted to hear the robot enjoying himself.

"M-Mettaton!" Aphys' soft, panting whimper could barely be heard in between the noisy slap of wet metal against drenched scales.

"H-Hmm?" He growled.

"I-I'm…I-It's.. _.A-Ahh!_ " Before she could warn him, her whole body spasmed and clenched, like a tight, wet fist around his cocks while he pumped himself inside of her. As the scientist spasmed, Mettaton held on and grit his teeth. Increasing the wild buck of his hips in order to milk ever one of those pulsing twitches riding along the length of his cocks. His vision began to blur and there was a wild buzzing in his head, but he tried to make it last. Wringing out every last shudder and working to make Alphys' pleasure last as long as he could manage.

But the tight grip of her muscles proved to be too much. The wildly pulsing heart resting within his soulbox pumped and glowed fiercely, nearly blinding him before he shut his eyes. Pleasure soared, flooding his entire frame until he could only manage to slam his hips forward on last time and cry out. Shuddering all over, eyes shut tight, Mettaton groaned loudly as his body emptied into Alphys'. Thick, hot liquid flooding into both of her holes that seemed to please Alphys to no end. Making her squirm on his cocks and tighten around him some more, body instinctively milking him for every drop he could manage. And there was quite a lot. He made sure of that. The thick fluid filled Alphys up so much that with a gratuitous squelch of a noise it began to spurt out of her tightly stretched holes, making a sticky mess between their bodies and across the thick expanse of Alphys' ass.

Mettaton shuddered once or twice more as the flood of it died down, his cocks giving a feeble shudder before finally emptying the last few pulses of their loads. He sighed heavily and reopened his eyes, taking a good look at the white goo slid across Alphys' scales and dripped down Mettaton's abdomen. Satisfaction warmed him. And though he didn't want to part from the gentle flexing squeeze of her aftershocks, he just had to see the end result close up. He pulled back slowly, smirking at the way Alphys shivered and whined before going limp again. And with a messy pop, both of his cocks came free, springing straight up once more as if ready for another round. Technically they were always ready, that was how they were designed, but Mettaton himself was drained. Instead he sat back on his heels and spread Alphys' ass infront of him. Watching in pleasure as thick globs of white began flooding from both of Alphys' holes, dripping down against the equally white sheets beneath her. Pride filled him, almost as strong as the pleasure from their intense fucking. He licked his lips and reached down to run a finger from her gaping pussy up to her stretched ass spreading his fluids around until Alphys cried out and squirmed.

"M-Mettaton..! Q-Quit it!" She squeaked, burying her face against her pillow. "Y-You messed up my bed again!" She complained quietly, but from the way her body was so limp and content, he doubted she minded.

"Sorry about that.~" Mettaton purred, sounding anything but. Done teasing her, he crawled over and lowered himself onto the bed beside her limp body, catching her attention by running a palm over the top of her head. When the blushing female glanced over at him, looking like a hot mess from all the squirming and wailing she had been doing, he grinned. "So how was my check-up? Am I up to code, my darling Dr. Alphys~?"

A hot blush bloomed across Alphys' face anew and she buried her face against her pillow again, ignoring Mettaton's amused chuckle as he looped an arm around her. Forcibly tugging her body close and pressing a loving kiss to the top of her head.

 _-end-_


End file.
